The dipper light curve of V715 Per: is there dust in the magnetosphere?

TL;DR

This study models the dipper light curve of V715 Per, suggesting that dust within the magnetosphere, influenced by magnetic field geometry and sublimation processes, causes the observed optical dips.

Contribution

It introduces a magnetospheric dust distribution model explaining the dipper light curve, incorporating dust evaporation and magnetic field misalignment effects.

Findings

Dust exists inside the magnetosphere at the disk truncation radius.

Optically thin dust layer causes extinction in the light curve.

Dust rapidly moves inward and sublimates, but a transient dust layer persists.

Abstract

The dipper optical light curves in young stellar objects are commonly interpreted as partial or total occultation of the stellar radiation by dust surrounding the star. In this work, we analyze the amplitude of the optical light curve of V715 Per, located in the young star forming region IC 348. Observations gathered over the years suggest that the light curve can be explained by dust extinction events. In our model, the dust is distributed inside the magnetosphere according to the strength of the stellar magnetic field. The dust distribution is modulated by the vertical component of the field, whose axis is misaligned with respect to the rotational axis. We include a model for the evaporation of the dust reaching the magnetosphere in order to consistently calculate its distribution. For V715 Per, there is dust in the optically thick warp at the disk truncation radius. We suggest that the optical light curve is explained by extinction caused by dust reaching inside the magnetosphere. The dust distribution is optically thin and due to the high temperature and low density, it cannot survive for a long time. However because the grains rapidly move towards the stellar surface and the sublimation is not instantaneous, there is a layer of dust covering the magnetosphere responsible for the extinction. Dust surviving the harsh conditions of the magnetospheric accretion flow may be responsible for some of the dipper light curves.